Wrench



' May 25, 1943.

o. JOHNSON 2,320,083

1. WRENCH Filed Jan. 29, 1942 /7 I I I v IN VEN TOR. A 05cm? JOHNS'O/Y, 0CHSD. if v BY [45/7 MJOH/YSO/V.

Patented May 25, 1943 Island, N. Y., by Elsa M. Johnson, administratrix, Bayside, Long Island, N. Y., assignor of three-cighths N. Y.

to Gunnar Burman, New York,

Application January 29, 1942, Serial No. 428,679

2 Claims.

This invention relates to wrenches and more particularly pipe wrenches and embodies certain improvements on Patent No. 1,754,684, issued April 15, 1930 to Oscar Johnson. In said prior patent there is disclosed a wrench of the type known generally as a chain wrench in that a chain associated with an appropriate handle may, by virtue of certain camming surfaces, be caused to Wrap tightly about a pipe, so that the pipe may be rotated to screw or unscrew the same into or out of a coupling.

The present invention is a wrench of the same general type, but provides for a much stronger and more positive construction whereby slipping be 'in which head is mounted cooperating rocker links. To the opposite ends of these links a chain is anchored in such manner that, when the wrench is tilted relative to a pipe about which the chain is passed, the chain may be wrapped tightly about the pipe as the camming surface of the head traverses the circumference of the pipe. As the degree of tilt between. the head and the pipe increases, the chain is wrapped tighter and tighter about the pipe until they are practically locked together, whereupon further tilting of the head .V

will bring about rotation of the pipe.

An important feature of the present invention resides in so forming the head that the rocker links thereof are adapted, as the pipe is gripped, to come into engagement with fixed abutments formed in the head and as tension is exerted on the chain, it is directed largely against firm abutments which are well able to withstand the same and which serve to relieve pivots. associated with the rocker links, from undue strain.

Features of the invention, other than those adverted to. will be apparent from the hereinafter detailed description and claims, when read in conjunc ion with theaccornpanying drawing.

The accompanying drawing illustrates one practical embodiment of the invention, but the construction therein shown is to be understood as illustrative, only, and not as defining the limits of the invention.

Figure 1 is a side elevation of a wrench embodying the present invention with one half section of the head of the wrench removed, so as to better show the working parts.

Figure 2 is a perspective view of the Wrench parts shown in Figure 1 with the chain and pipe section removed.

Figure 3 is a plan view of Figure 1.

The wrench of this invention comprises a head formed in two half sections i, one of which is shown in Figures 1 and 2, the other section bein a duplicate. These sections are placed in face to face relation to collectively form the head. Each head section is provided with a shank 2 of cylindrical form and these two shanks are adapted to fit into a tubing of any desired length to form the handle H of the wrench.

The opposite lateral edges of each head section are provided with camming surfaces 3 and 4 which merge into an arcuate hollow 5 at the crown of the head, the low phases of the cam faces being "adjacent this hollow.

ries a rigid pin 9 extending into the corresponding hole 1 which forms a bearing therefor. The opposite ends of the rocker links are rounded and ,the recess 6 is shaped on such radius that the rocker links will, when rotated on the pins 9, closely conform to the periphery of the recesses 6 except adjacent the plane of the axis of the handle at which points are formed abutments l 0, l 1, l2 and I 3, as clearly shown in Figures 1 and 2.

With this arrangement, the rocker links are free to rotate through approximately 90 degrees, but at each terminus of this arcuate movement, the opposite end portions of such links come into firm engagement with complementarily shaped abutments, as clearly shown in Figure 2.

It will be seen from Figure 2 that the shank portion 2 projects somewhere from the near or inner face of the head section, so as to form a step l4 and when two such shanks are placed in face abutting relation, the associated head portions I will be spaced apart. Into the space thus provided are adapted to extend one end of each of two links l5 and IS. The link l5 constitutes the master link of a chain H which is secured to the outer end of the master link, while the inner end of the master link is perforated for the passage of a pin I8 which extends therethrough and is anchored at its opposite ends in alined holes in the corresponding ends of the rocker links 8. The other link I6 constitutes a locking link. One of its ends also extends into the space between the head sections and is perforated for the passage of a pin I9, the opposite ends of which are anchored in the corresponding ends of such rocker links.

The outer end of the locking ring I6 is bifurcated to permit the links of the chain IT to fit between the arms 26 of such bifurcated end, while the pins 2i of the chain are made to extend beyond the outside faces of the exterior links of the chain as shown best in Figure 3 and are adapted to be received within slots orchannels 22 formed on the inner faces of said arms 20. The

channeled arms 20 thus constitute'in'efiect closedfaced hooks for gripping the pins 2i of the chain" I in a manner similar to the hooks Id of the aforesaid patent. By making the outer faces of thehooks, solid, however, a much stronger construction results.

In the making of the wrench of this invention, certain factors should be carefully adhered to. For example, the peripheries of the recesses 6 should fit very close to the ends of the rocker links 8 particularly at the abutments Iii-I3 inclusive, so that when the greatest strain is placed upon the wrench, the ends of these rocker links may seat very firmly against such abutments and thus materially relieve the strain on the pivots I. Moreover the thickness of the links I5 and I6 should be substantially the same (with Very slight clearance) as the space between the head sections, so that the inner ends of the links I5 and I6 and the contiguous faces of the rocker links will be maintained in substantially face abutting relation. When this construction is followed, there will be practically no bending stresses imposed upon the pins I8 and I9 which bridge the space between .the rocker links and consequently, even though great force is exerted on the wrench, the strain on these pins would be almost entirely a cross axial sheering strain which the pins, being hardened, will be able to withstand. If the space between the head sections is materially greater than the thickness of the links [5 and I6, it is found that the pins I8 and H! are subjected to bending stresses which cause their breakage. When the parts are properly made,'however, as stated, the wrench parts will withstand tremendous force without damage.

In using a wrench made according to thi invention, the head of the wrench is brought into the position shown in full lines in Figure 1 with the pipe P opposite the hollows 5. The chain I1 i 'thereupon wrapped about the pipe, as shown, and appropriate pins 2| engaged with the hooked bifurcated end of the locking link I6. The hollows 5 permit the chain to be wrapped tighter about the pipe than would be possible if these hollows were absent and makes it feasible to use a head of smaller size than th absence of the hollows would allow.

When the parts are assembled on the pipe as shown in Figure 1, it will be noted that the channels 22 incline upwardly and thus the weight of the wrench will cause it to hang on the pipe and it will not inadvertently disengage and fall.

To grip the pipe the handle H is tilted, e. g., in a clockwise direction, asviewed in Figure 1, to bring the low phase of corresponding cam force without slippage.

surfaces 3 of the two head sections into engagement with the pipe P and, as this tilting continues, the cam surface 3 will circumferentially traverse the pipe until the shank 2 of the wrench head is in substantially the position indicated in dot and dash lines in this figure. By this time the links will have also moved to the dot and dash line position in this figure or as better shown into the full line position of Figure 2 where the opposite ends of these rocker arms are in engagement with the abutments I I and I2. By the time this condition has come to pass the chain will have become tightly wrapped about the pipe and the pipe will be so tightly gripped by the wrench that it may be turned with great If any slight slippage should occur, it will serve to cause the pipe to ride even higher onto the camming surface 3 and thereby accentuate the grip already existing, so

that further slippage cannot occur.

As long as the handle of the wrench is tilted in a clockwise direction, the pipe will be turned .in a corresponding direction, but if the handle of the wrench is retracted, i. e., tilted in a counterclockwise direction the chain will slip freely about the pipe toagain take a new grip when the direction of tilting is reversed. By virtue of this fact, the wrench may be operated with a ratchet action and without necessitating the removal of the wrench from the pipe. Furthermore the wrench can be operated with either the camming surfaces 3 or 4 in engagement with the pipe by merely swinging the handle from the right to the left, or vice versa, to engage the corresponding camming surfaces With the pipe.

When it is desired to remove the wrench from the pipe, it is only necessary to lift the wrench sufficiently to disengage the chain pin 2| from the bifurcated end of the locking link and this will disengage the chain so that the wrench may be removed.

I wish to call particular attention to the fact that at those times when the wrench will be called upon to take the greatest strain, the parts will be in the positions shown in Figure 2 and it will be apparent from thi figure that at this time, the upper right hand ends of the two rocker links will be firmly seated against the abutments I I, so that the pull of the chain will be approximately practically through solid metal directly from the pin I9 to the abutments II. The opposite ends of the rocker links will rest firmly against the abutments I2 and this assures maximum eificiency in gripping the'pipe with maximum ability of the wrench parts to withstand the great strains, to which they are subjected at this time. All operating parts of the wrench, such as the camming faces 3 and 4 and all pivot pins and bearings of the links are appropriately hardened so as to withstand continued use without undue wear. Furthermore the chain is made sufiiciently long so that the wrench may operate upon pipes of widely varying sizes, it being understood that the pin 2| of the chain which engages with the hooked end of the locking link will depend upon the diameter of the pipe to be gripped.

The wrench of this invention possesses great strength. It is thoroughly reliable and will operate upon all kinds of pipe without injury thereto. It grip the pipe positively but in such manner that it will not tear or gouge the pipe like the jaws of a Stillson wrench and by proper engineering design of the parts the wrench may be made relatively light with respect to th work to be performed thereby.

Having thus fully described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A wrench comprising a head having ahandle and provided peripherally with a hollow merging into oppositely facing camming surfaces with the low phases of said camming surfaces adjacent said hollow, the head having a slot passing through said hollow and camming surfaces and intersecting a recess formed within the head, facially spaced apart rocker links positioned within said recess on opposite sides of said slot and having medial trunnions with bearings in the head eccentric to said camming surfaces, pins supported by the opposite ends of said rocker links and bridging the space between them, a master link connected to one of the rocker link pins at its inner end and extending through said slot with a flexible link chain connected to its outer end,

2. A wrench comprising two complementary head sections spaced apart to form between them a slot and having handle shanks in face abutting relation, a handle secured to said shanks coland a locking link pivotally connected to the other lectively, the crown of the head directly opposite the shanks being provided with a hollow merging into gradually rising peripheral camming sections in the direction of the shanks, a recess formed within the head and communicating with said slot, facially spaced apart rocker links positioned within said recess with pins connecting their opposite ends, said rocker links being pivoted for rocking movement on trunnions positioned substantially midway of their ends, a master link connected to one of the rocker link pins at its inner end and extending through said slot with a flexible link chain connected to its outer end, and a locking link pivotally connected to the other rocker link pin and extending through said slot and provided at its outer end with a hook to selectively engage the link pins of said chain, there being provided within the recess of the head rigid abutments positioned in the path of rocker links to be firmly engaged thereby as the rocker links rock into gripping positions.

ELSA M. JOHNSON, Administratrizc of the Estate of Oscar Johnson,

Deceased. 

